Very low oil pressure - Ford Forums - Mustang Forum, Ford Trucks, Ford Focus and Ford Cars

04-16-2003, 16:50

Just recently the oil pressure on my 81' F-150 300 I-6 is reading very low especialy when warmed up. When first started it is ok.
Could the oil pump be going bad ~192K miles on the engine. And if so how hard is it to install a new oil pump. Has anyone had one replaced and what is the average cost to replace it.

Thanks

big1 · 04-18-2003, 07:06

The bearing's are getting worn due to age, but these are very stout engine's and survive a lot of abuse. Oil pump replacement is a straight forward job in most case's. Unbolt engine mount's, raise and support engine,drain oil, remove oil pan, remove oil pump, install new pump, install oil pan w/ new gasket, lower engine, tighten engine mount's, pour in oil, pull coil wire, crankover engine to prime the system,reinstall coil wire,start engine and check for leak's

09-14-2003, 14:11

If you have kept oil changed in that 300-I6 then all you have to do is change out the oil sending unit which is a diaphram looking gismo down and toward the back from the oil dipstick and if you want to really be amazed change the oil and use a ford F-1A oil filter and that alone will make a big difference. Let me know if that helped any. last resort is to replace crank bearings. The inline 6 usually outlast the vehicle is taken care of.

89F150 · 09-14-2003, 18:25

Is this the stock guage your reading from? Big 1, arn't the guages just a switch and when it reads over 7psi (something like that) it moves. They dont actually show the pressure.

351w · 09-14-2003, 21:42

i am wondering when you last had the oil changed in this and was it 10w-30 oil that was put into it.
did you just notice this happening suddenly or has it been getting worse over time.
there are several things that effect your oil pressure !

big1 · 09-15-2003, 05:56

In the 81 model's the gauge did give an actual pressure reading, but they were very inaccurate.
You could try going to a heavier oil, say 20w50, that may help.
Check your gauge against a mechanical gauge.

351w · 09-15-2003, 18:59

i tried running 10w-30 rotella T in my truck once and it was exactly as mmsergent decribed.
it was fine in the morning when i started it but 10 min later i had almost no pressure so it only lasted 3 days till i replaced it with 15w-45 rotella and the problem was solved.

09-15-2003, 22:49

I had the exact same problem in my '87. I also have the straight 6 and thought that my oil pump was bad. I then thought about it a little more and it was the oil presure sensor right by the dip-stick with the one wire on it. It wouldn't hurt to try replacing it first. They are only about $15 and you don't have to tear anything apart. It fixed my problem. Try it and let me know.

never2low · 09-21-2003, 21:05

try putting some Lucas in the crank case.

09-29-2003, 18:41

I have an '87 F150 4x4, 4.9 I6 with 225,000 miles. at about 200k miles, I started seeing something similar. Mostly when I was running on the highway and would pull up to a stop light, I'd lose almost all oil pressure for a second or so. I thought it was bearing, oil pump or something else, and decided to park the truck, since it wasn't my primary vehicle. After my other vehicle was totaled by drunk driver, I decided to work on the truck. I pulled the oil pan off and the screen on the pickup tube to the oil pump was completely stopped up. I cleaned the screen, took the oil pump out, it looked fine, so I put it back together and had normal oil pressure again. Only bad thing was, now I have a small leak in the oil pan, which I've tried to fix twice. It's hard to get the oil pan back in and keep the gasket straight.

But I bought a 2004 F150, so I'm reluctantly selling the '87. It has been a great truck and still runs very good.